1. Field of the Invention
The present invention relates to a fuel saving apparatus for an internal combustion engine and, more particularly, to an apparatus having a novel spark plug allowing predetermined cylinders to be vented through the spark plugs therein simultaneously with fuel cutoff to those cylinders.
2. Description of the Prior Art
It is well known to conserve fuel in an internal combustion engine by cutting various of the cylinders of the engine out of firing operation when less than full load conditions are imposed on the engine. U.S. Pat. No. 1,201,055 issued to Jones is an early example of this principle. In Jones, supra, the normal exhaust valves of the unused cylinders are operated by a rod to port the cylinders to atmosphere through the exhaust manifold while butterfly valves are simultaneously operated by a mechanical linkage to cut off the fuel flow to the cylinders. U.S. Pat. No. 2,745,391 to Winkler is a further example of another cylinder cutout device which closes the normal intake and exhaust valves for the cylinders in the engine to conserve fuel.
Those devices which cut out selected cylinders by operating the normal intake and exhaust valves for those cylinders have various disadvantages. For example, such devices must be quite complex to couple the valves to their operating camshaft and yet allow the valves to be selectively uncoupled therefrom to cut the cylinder out of operation. As shown in Winkler, supra, and U.S. Pat. No. 3,964,455 to Brown, such valve operating mechanisms often include complicated hydraulic actuators. Such actuators increase the complexity and cost of the device and also are prone to mechanical breakdown. Purely mechanical connections for uncoupling the intake and exhaust valves are similarly complicated and difficult to keep running in error free operation considering the continual motion of the intake and exhaust valves as operated by the camshaft.